The present invention relates to a stapling device for use in the fixation of endovascular grafts to the walls of vessels. Fixation of grafts utilizing the present invention may be conducted during initial implantation. However, the present invention may also be utilized to arrest the vexing complication of proximal or distal migrations following the prior implantation of such grafts.
It is well known that endovascular grafts may be inserted into the human body during numerous medical procedures. Grafts are typically inserted into vessels and held in place by friction, such as with self-expanding or balloon expandable stents. The grafts may also be affixed to vessels with hooks or barbs.
The grafts may be formed from synthetic materials, such as polyester, expanded polytetraflouroethylene (“ePTFE”), or others. The grafts may also be formed of natural vessels harvested from other areas of the body or from a donor mammal. Notwithstanding the various materials utilized, migration of the grafts over time remains a problem.
Caudad device migration is known to lead to a Type 1 endoleak with aneurysm sac reperfusion, enlargement and rupture. Cephalad device migration may lead to coverage of the renal artery orifices and renal insufficiency.
Such device migration is caused by many factors. One known factor is poor patient selection. Patients with cone shaped aortic necks, severe neck tortuosity, short necks or who have a laminated thrombus present at the landing site are generally susceptible to device migration problems. Other device migration issues are caused by changing aortic morphology following device implantation. Finally, migration may be caused by device structural fatigue and device design related issues. Even absent these conditions, device migration has been found.
Treatment of caudad migrations have traditionally been conducted by the addition of “sleeves” to the proximal end of the graft in an effort to regain purchase between the graft and the vessel it is attached to in order to maintain a seal between the two. More drastic options include resorting to conventional surgery. These late conversions are, unfortunately, associated with a high mortality rate.
Treatment options for the cephalad migrations are even less attractive. In the face of continued migration, resignation may be the only option as such migration may lead to renal insufficiency requiring hemodialysis. To permit device removal, a typical conversion in this case involves supra-celiac aortic cross-clamping, and its associated problems.
Prior attempts at fixation of migrating devices, including additions of hooks, barbs, tackers, and other fastening devices have proven to be insufficient or impractical. It would therefore be advantageous to provide an endovascular stapling device which may be used to adequately arrest existing migrations, as well as secure new grafts in a manner likely to eliminate future migration. Actual fixation of the graft to the aortic neck at multiple points will also prevent the aorta itself from enlarging.